I have been using it very happily for about a month now, but a few days ago the bell sound that helps me switch from running to resting and back without looking on my AppleWatch has suddenly stopped working. Now I only get a buzz, but that’s too faint to notice during workouts most of the time.

What is wrong ?

Answer :

The solution is so simple, you may have overlooked it :

on your AppleWatch in standard view, slide up to see the buttons for WiFi, Airplane Mode, Night Mode, etc.

slide up again to see the rest of the buttons

bottom left, you’ll see the Bell-button crossed-out in red : click it to reactivate (so the button’s color will be back to gray)

now, your (bell) sound will be back when you ar e using the app on your AppleWatch